This invention relates to an inclination detector adjusting device for vessel propulsion units and more particularly to an improved position sensing device for marine outboard drives and method for adjusting it.
In a variety of marine applications, there is provided a position sensing device for sensing the trim angle of the outboard drive. Such trim angle sensors may be used either in conjunction with outboard motors or with the outboard drive section of an inboard/outboard drive. The trim position sensor is used for a wide variety of purposes and may provide merely an indication of trim angle or, in some instances, may provide an input signal to a more complicated control system. For example, this type of device can be used in conjunction with automatic trim adjustors, trim adjustors that maintain the trim in the desired condition to obtain a desired watercraft running condition or a wide variety of other applications.
The trim position sensor normally is comprised of a housing that is adjustably affixed to one component of the outboard drive and a moveable element that is movably connected to the housing and which is fixed for movement with another component of the outboard drive. As a result of the relative movement between the outboard drive components, the elements of the trim position sensor change in relative position and an output signal is provided that varies in response to the angular position.
Although the aforenoted type of device is particularly advantageous, it is necessary to accurately mount the trim position sensor on the supporting outboard drive component in an accurate condition. This is necessary to permit the 0.degree. adjustment of the device so that the output reading will be accurate in response to the actual angular position of the components.
FIG. 1 of the drawings illustrates a typical trim position sensor and its method of mounting and FIG. 2 indicates the way in which the initial position of the sensor is set. These figures depict and illustrate the problems attendant with conventional prior art constructions.
Referring first to FIG. 1, a trim position sensor is identified generally by the reference numeral 11 and includes an outer housing 12 that has a pair of mounting flanges 13. These mounting flanges 13 are provided with elongated or arcuate slots 14 that pass respective threaded fasteners 15. The fasteners 15 may be loosened so as to permit adjustment of the housing 12 and then are locked in place.
The sensor 11 further includes a moveable element 16 that is connected to another component of the outboard drive for direct movement with that component. The relative positions of the element 16 and housing 12 will provide a signal indicative of the position of the outboard drive component.
Typically, the indicating device 11 may be a potentiometer and FIG. 2 shows schematically how the potentiometer is utilized in conjunction with the circuit. The potentiometer includes a winding 17 that is fixed within the housing 12 and which cooperates with a wiper 18 that is fixed for movement with the element 16. A constant voltage supply is applied to the potentiometer winding 17 from a constant voltage source through terminals IN and E. This input voltage is indicated by the signal "Vie". The voltage across one of the terminals and the wiper terminal (OUT) indicated by the signal "Voe" provides a voltage signal indicative of the angular position.
In order to initially set the position of the potentiometer or position sensor 11, the device is loosely fastened in place and a voltage supply is applied to the device. The device is then rotated with the wiper in a preset position until a predetermined potential is determined at the output Voe. However, the exact setting of the device is sometimes impossible in spite of accurate measurement of the resistance between the terminals OUT and E because of large variations in the total resistance between the terminals IN and E of the sensor. In some vessels, it is also impossible to move the sensor in small increments while reading a meter indication for setting. Furthermore, a voltage stabilizer and high precision digital circuit tester are essential for accurate setting.
It is, therefore, a principal object of this invention to provide an improved inclination sensor or trim position sensor for a marine outboard drive that is easier to adjust and does not require external components.
It is a further object of this invention to provide an improved position sensor and method for sensing a position sensor that can be utilized with marine outboard drives.